Present day electronic equipment such as frequency synthesizers being utilized in citizen band transceivers often require "D" flip-flops. These bistable multi-vibrators have master and slave portions. Generally, D flip-flops transfer binary information existing at the inputs of the master portion to the slave portion thereof in response to a predetermined transition of a clock signal. This data is stored in and provided at the output terminals of the flip-flop by the slave portion until the next predetermined transition of the clock signal, at which time the data then being supplied to the input terminals of the master portion is stored in the slave portion.
It is desirable for D flip-flops to have high speed-power products. In this context, speed refers to the maximum rate at which the flip-flop can handle data and power is a function of the magnitude of the current drawn by the flip-flop. Low current drain is a particularly advantageous characteristic for flip-flops included in battery operated equipment or in (large scale integration) LSI chips, where it is important to minimize power dissipation. Moreover, it is desirable in some applications for D flip-flops to have low operating voltages to that they can be utilized in portable battery operated equipment or in circuits powered by the electrical system of an automotive vehicle. Also, it is desirable for D flip-flop circuits to have configurations which are simple, to maximize reliability and which take up a minimum amount of space if provided in integrated circuit form. Furthermore, some frequency synthesizer designs, for instance, require D flip-flops which have a speed of operation which is faster than that of I.sup.2 L configurations, which are compatible with I.sup.2 L circuitry but which are not as complex as prior art emitter coupled logic (ECL) configurations. Most prior art "D" flip-flop configurations do not have one or more of the aforementioned desirable characteristics.